Chamfer strip

ABSTRACT

A strip of plastic, or the like material, used for locating a concrete form in the construction of a monolithic slab and beam construction.

D United States Patent 11 1 1111 3,782,680 Hopkins Jan. 1, 1974 [54] CHAMFER STRIP 2,940,152 6/1960 Riehl 249/188 2,953,835 9/1960 Armstrong et a1.... 249/188 [76] Inventor- Davd Hopkms, 506 McLeod 3,260,493 7/1966 Beckham 249/194 x Hartsv111e, S.C. 29550 FOREIGN PATENTS OR APPLICATIONS [22] 1971 549,511 2/1923 France 249 2 [21] Appl. No.: 187,708

Primary Examiner-J. Spencer OverhoIser Assistant Examiner-DeWalden W. Jones [52] US. Cl. 249/188, 249/176 51 1111. c1 .1 B28b 7/28 McBrde [58] Field of Search 249/188, 176, 177,

249/142, 63, 31, 2s, 9, 194 [57] ABSTRACT A strip of plastic, or the like material, used for locat- [56] References Cited ing a concrete form in the construction of a mono- UNITED STATES PATENTS lithic slab and beam construction.

1,846,196 2/1932 Goldsmith 249/31 3 Claims, 5 Drawing Figures PATENI gJM 1 197-? FIG. 3

FIG. 2'

INVENTOR.

DAVID' L. HOPKINS CHAMFER STRIP In concrete construction, it is standard procedure to utilize a U-shaped pan to in effect void an area and by spacing these pans form a slab and a beam of concrete which will function as a floor and ceiling upon the removal of the pan and support structure. It is also known to utilize domes in a similar type of construction in which there would be provided a honeycomb effect with the joists being at right angles to one another. It is difficult to locate these pans and domes on a support structure in a manner to completely preclude any lateral movement without complicated devices. It is even more difficult to provide a chamferred edge on the bottom of the beam construction.

In the past it has been known to nail a triangular piece of material directly to the support structure, toenail the pan against the triangular member or nail a back-up piece of material to the support structure behind the pan to prevent lateral displacement in the direction opposite to that of the triangular member which forms the chamfered edge. A triangular rubber member located at the lower corner of a joist form and secured with nails has also been known. Metalforms for joist construction have flanges which meetalong the soffit and leave an unsightly seam. Obviously, these constructions create a tremendously difiicult construction for removal without damage to the concrete construction.

It has also been known to use metallic members such as that shown in US. Pat. No. 1,846,196 issued to W. M. Goldsmith on Feb. 23, 1932 for forming the chamfered edge. These constructions have the critical disadvantage of not retaining the edges of the pan against lateral displacement. This is even more true under modern conditions of construction wherein heavy reinforcing is located in the structures and the pans and domes receive extremely damaging treatment. Moreover, the use of heavyweight concrete and vibrators contribute to the tendency for the pan leg to compress inwardly and thereby give a greater width to the joist or beam. This causes a poor construction because the concrete filters between the side of the pan and the chamfer strip.

A further disadvantage of the priorart is the inability to form right angular joist or beam constructions with known strips used in the provision of the chamfer and in the location of the pans and domes.

In view of the above disadvantages, it is an object of the instant invention to provide a chamfer strip which easily and accurately locates the forrnwork for concrete construction.

Another object of the instant invention is to provide an integral chamfer strip which receives and prevents the lateral displacement of the edge of a form used in a concrete construction.

Still another object of the instant invention is to provide a chamfer strip which receives the edge of a concrete form and prevents lateral dislocation thereof and which may be easily attached and aligned on the support structure.

Still another object of the instant invention is to provide a construction wherein a form member can be easily, aligned and fit within a chamfer strip to permit the formation of a mold for a concrete construction.

The instant invention'overcomes the disadvantages of the prior art and accomplishes the above objectives in the provision of an elongated strip having a triangular chamfer portion which is spaced by a groove from a ridge and integrally formed with a base having a flange. The upright edge of the pan fits within the groove and the flange permits securement of the chamfer strip to the supporting structure.

The invention may best be understood by reference to the following description taken in conjunction with the accompanying drawings wherein like numerals refer to like elements and in which:

FIG. 1 is a cross-sectional view of a concrete structure and form constructed in accordance with the instant invention;

FIG. 2 is a top view of the chamfer strip of the instant invention;

FIG. 3 is a perspective view of a portion of the chamfer strip of the instant invention;

FIG. 4 shows a cross-sectional view of an alternative embodiment of the invention; and

FIG. 5 shows a cross-sectional view of another embodiment of the instant invention.

Referring now to the drawings and more particularly to FIG. 3 wherein the novel chamfer strip 10 is shown to include a flat base portion 12 and a chamfer portion 14. Chamfer portion 14 is substantially triangular in shape having angular surface I6 and under surface 18. However, it is to be noted that chamfer portion 14 could be of any desired configuration, such as rounded or stepped.

Ridge 20 extends upwardly from base 12 and has inner or forward upright surface 22 which is slightly angled to the vertical in relationship to base 12. Ridge 20 includes top edge 24 and outer or rear upright surface 26. Substantially horizontal face 28 forms the upper surface of flange 32 which would be formed of upper surface 28, the lower surface of base 12 and upright edge 38. It is noted from FIG. 3 that groove 30 is formed between surfaces 18 and 22 of chamfer portion 14 and ridge 2%), respectively. Flange 32 may be provided with apertures 34 for receiving securement members suchas nails in the utilization of chamfer strip 10.

Referring to FIG. I wherein floor and ceiling construction 42 is shown to include slab 44 and joist 46 formed of concrete or similar material.

Form 41 is mounted in chamfer strips 10 which are located on support 5%. Support 56 is maintained in proper position by shoring 52. It is to be understood that although the construction shown in FIG. I only includes vertical shoring 52 and a horizontal planar support 50, there are alternative configurations of the support for chamfer strips 1% and forms 40. It is noted that nails 54 secure chamfer strips 10 to supports 50 through apertures 34. In many instances it may be advisable to use a two-headed nail to permit easy removal of the chamfer strips It.

The alternative embodiment of the chamfer strip shown in FIG. 4 provides a rounded corner on the joist or beam. The basic portion of strip 50 is identical to that of the embodiment of FIG. 3. Chamfer strip 60 has base 12 with ridge 2t} and flange 32. Chamfer portion 62 has concave upper surface 64 and rear surface 66 that forms groove 34) for receiving the lower edge of form 40.

Chamfer strip 70 is substantially the reverse of strip 10 in that angular surface 72 is connected by upright 74 to base 12. This construction also forms groove 30 for receiving and accurately locating the edge of form 40.

In operation, it is conventional to put the shoring and support structures in place and by putting some type of marking on support 50 to effect alignment of chamfer strips 10. Once strips have been aligned and properly located with nails 54, it is a simple and easily accomplished process to mount forms 40 in grooves 30. The reinforcing steel is then located in a conventional manner and the concrete for forming the floor and ceiling construction 42 is placed.

Once the concrete has set, it is possible to remove the construction by removing shoring 52 and lower support 50 with the attendant form 40 and chamfer strip 10. Depending upon the type of support structure, it may be possible, where stringers have been utilized, to remove nails 54 and effect the individual removal of chamfer strip 10 and pan 40.

The instant invention provides a chamfer strip which is light in weight yet structurally strong and capable of a multitude of uses. Moreover, it is possible to effect various surfaces on the form 40 and face 16 of chamfer strip 10 and thereby efiect various surfaces on the form 40 and face 16 of chamfer strip 10 and thereby effect a desirable characteristic to the surfaces of the poured concrete. The instant invention is economically produced as for example by extrusion of a plastic material such as polyethylene, polystyrene, polyvinylchoside, polypropylene, ABS (Acrylonitrile-Butadiene- Styrene), or polyurethane, but could easily be injection molded.

FIG. 2 shows an alternative construction in which a linear section of chamfer strip 10 has been mitered and put in position at a right angle to another mitered chamfer strip 10 such that a corner construction is formed and may be used at the intersection of beams and with the dome construction which is precluded by previously known devices. It is very simple for the contractor personnel to cut the chamfer strip 10 at the construction site to any desired length.

The ease of manufacture of the instant chamfer strip is readily observed, as well as the potential for injection molding where specific given sizes are required. This would permit a mitered construction readily available for use with dome constructions and constructions where there are joists at right angles to one another.

I claim 1. A chamfer strip for properly locating and restraining a form comprising: a flat base portion, a chamfer portion extending angularly upwardly from said base portion at one end thereof; a ridge portion extending upwardly from said base portion and spaced from said chamfer portion; said base portion extending beyond said ridge portion to provide attachment means for securing the chamfer strip to support structure; and said base, chamfer portion and ridge portion being formed integrally of a plastic material from the group consisting of ABS, polystyrene, polyethylene and polyurethane, whereby a longitudinal groove is formed for receiving the upright edge of the form.

2. The chamfer strip of claim 1 wherein the end of said strip is beveled to permit longitudinally angular fixation of the two chamfer strips to permit construction of forms at angles to one another.

3. The chamfer strip of claim 1 wherein said chamfer portion has a concave upper surface. 

1. A chamfer strip for properly locating and restraining a form comprising: a flat base portion, a chamfer portion extending angularly upwardly from said base portion at one end thereof; a ridge portion extending upwardly from said base portion and spaced from said chamfer portion; said base portion extending beyond said ridge portion to provide attachment means for securing the chamfer strip to support structure; and said base, chamfer portion and ridge portion being formed integrally of a plastic material from the group consisting of ABS, polystyrene, polyethylene and polyurethane, whereby a longitudinal groove is formed for receiving the upright edge of the form.
 2. The chamfer strip of claim 1 wherein the end of said strip is beveled to permit longitudinally angular fixation of the two chamfer strips to permit construction of forms at angles to one another.
 3. The chamfer strip of claim 1 wherein said chamfer portion has a concave upper surface. 